I'm currently trying to get all users from wp_users that have no matching ID entry in wp_usermeta (matching on user_id).
I have a site with a very large user base that currently has thousands of spam users.
The following query is returning no records:
SELECT * FROM wp_users WHERE ID NOT IN ( SELECT user_id FROM wp_usermeta);
I've already removed the bad records from the meta table which is why I need to query to find only the records with no associated ID in wp_users.